Gold solvent for refractory ores.



NITEI) STATES PATENT OFFICE.

DAVID MOSHER, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE-HALF TO PETER A. WAGNER'AND GEORGE A. I-IINKELBEIN, OF SAME PLACE.

' GOLD SOLVENT FOR REFRACTO RY ORES.

SPECIFICATION forming part of Letters Patent No. 654,838, dated July 31, 1900.

Application filed April 26, 1900. Serial No. 14,475. (No specimens.)

T aZZ whom-t it may concern..-

Be it known that 1, DAVID MosHER,a citizen of the United States, residing in the city and county of San Francisco, State of California,

have invented an Improvement in Gold Solvents for Refractory Ores; and I hereby declare the followingto be a full, clear, and exact description of the same.

My invention relates to the treatment of base gold ores and its objects are to reduce the cost and economize the gold solvent to its fullest extent.

The attempt to adopt bromin as a gold solvent in the treatment of refractory ores and I 5 regain the bromin from the spent gold solu tion has not met With anyeconomical success, While a solution of bromin in hydrochloric acid (muriatic acid) offers no advantages, as no attempt is made to also utilize the hydrozo chloric acid as a gold solvent, which is the aim of this invention. The Well-known solubility of bromin in hydrochloric acid (in practice one pound bromin in eight pounds commercial muriatic acid 21 Baum) has up to 2 5 the present not been advantageously applied to the treatment of ores, as the muriatic acid has been partially or completely neutralized by means of soda-ash (N a CO or limestone, (CaCO nullifyin g the most important factor of the process. I have found that by the addition of any of the alkaline oxygen salts the hydrochloric acid can be fully utilized and is transformed conjointly with the bromin into a most powerful gold solvent. I use by preference potassium permanganate, (K Mn O which can be obtained at low cost and which answers the purpose most eifectively, although equivalents can be adopted instead. In adopting this process for the leaching of c ores I add only a small proportion of the oxygen salt to the hydrochloric solution of bromin, so as to develop no free chlorin in any noxious quantity. 7

In practice I proceed as follows: In a leadlined barrel holding about ten tons of crushed and roasted ore I add enough Water to produce a semiliquid pulp. A solution of fifteen pounds bromin in one hundred and twenty pounds commercial hydrochloric acid 21 Baum is then poured in, and finally from ten to fifteen pounds potassium permanganate, (K Mn O dry and in crystal form, after which the manhole is sealed and the barrel set revolving, as in the Well-known chlorination process. About one and one -fourth pounds potential chlorin will be slowly generated for each pound potassium permanganate (K Mn O lused, as it is slowly dissolved in the solution. Sufficient pressure will also be induced in the barrel and the gold-rapidly 6e and completely dissolved,- while the solvent capacity of the solution will with little addi tional cost be more than doubled.

For well-roasted and slightly-base ores the above quantity of chemicals may be materi ally reduced. The precipitation is best offected by sulfurous acid and hydrogen sulfid, which is the method preferably in use for precipitating precious metals out of halogen solutions and needs no description. s

I have not deemed it necessary to enter into the mechanical details 'of the process, the Colorado chlorination plants using roasting furnaces and lead-lined revolving barrels be ing well suited to my purpose.

I do not claim the solution of bromin in hydrochloric acid; but

What I desire to secure by Letters Pa tent 1s'-' 1. The process of treating refractory ores containing gold, consisting in reducing the ore to a pulp, adding thereto a solution of bromin in hydrochloric acid and then adding an oxygen salt of an alkali metal capable of reacting on hydrochloric acid to evolve free chlorin to transform the hydrochloric acid conjointly with the bromin into strong gold solvent. 7

2. The process of treating refractory ores consisting in reducing the ore to a pulp, add- 9o ing thereto a solution of bromin in hydrochloric acid, then adding potassium permanganate and thereby liberating chlorin from the hydrochloric acid to transform the acid ,7

and bromin into a more eifective solvent. 5 3'. The process of treating refractory ores consisting in reducing the ore to a pulp, adding thereto a solution of about fifteen pounds of bromin in one hundred and twenty pounds of commercial hydrochloric acid 21 Baum, 10o

then adding potassium permanganate in dry rating the mass to slowly liberate chlorin and and crystalform to slowly'generate ehl'orin. then precipitating the precions'metals.

4. The process of treating refractory'ores 'In witness whereof I have hereunto set my consisting in reducing the ore to a pulp; 'addhand. 5 ing thereto a solution. of bromin in hydro- DAVID MOSHER.

chlorie acid; then adding an oxygen salt of I v an alkali metal capable of resin ting onhydrochlorieacid to evolve free c hlorin then agi- Witnesses:

(S. H. NOURSE,-. s

JESSIE -O. BRODIE. e 

